#include<iostream>
using namespace std;
class A{
	public:
		int val;
		A(int n=0){
			val=n;
		};
		int &GetObj(){
			return val;
		}
};
int main(){
	A a;
	cout<<a.val<<endl;
	a.GetObj()=5;
	cout<<a.val<<endl;
}